Large volume infusions of medicaments are regularly given by microprocessor-controlled delivery devices such as infusion pumps, delivering the medicament from a passive reservoir such as a vial, bottle, collapsible bag or pre-filled cassette.
A passive reservoir is not subjected to positive pressure in use, and is associated in use with a delivery device applied to a patient supply line leading from the passive reservoir. Such delivery devices are many and varied and include peristaltic pumps and reciprocating pumps, both of which apply positive pressure on the patient supply line and not on the passive reservoir itself.
Also a delivery device in the form of a drip feed controller may control delivery of the medicament in the patient supply line, based on an electronic count of drips of medicament produced from the passive reservoir simply under the force of gravity.
The present invention is not limited to any particular form of passive reservoir or delivery device, although it is preferably, but not necessarily, applicable to pre-filled passive reservoirs for medicament, i.e. those filled and marketed by the pharmaceutical medicament manufacturer.
A non-limiting example of such a reservoir would be a pre-filled collapsible plastics bag, of the type often suspended from a stand in use in a hospital ward, to take advantage of gravitational force in delivering medicament from the bag.
Further non-limiting examples of such reservoirs are bottles and large vials, each of which are often suspended from a stand for use in a hospital ward or operating theatre. In each case the medicament may be sucked from the reservoir or may flow out under gravity. These systems comprising bottles or vials will require air to be entrained, usually through a bacterial filter, in use.
Yet further non-limiting examples of such reservoirs are cassettes or cartridges (optionally pre-filled with medicament). Such reservoirs may be suspended from a stand for use in a hospital ward or operating theatre. In an alternative they may be used in ambulatory devices for infusion of, for example, chemotherapeutic agents, insulin or agents for control of pain.
Conventionally, a passive reservoir of whatever type is filled by the pharmaceutical company and supplied to a hospital where the reservoir is connected to the delivery device by a doctor or nurse. The delivery device comprises a computer control means for controlling the medicament flow and comprising a keyboard and display means. The doctor or nurse can program the computer control means through the keyboard, setting for example the flow rate, duration of the infusion, or the maximum volume to be delivered.